During lesson, Poonam, 9, is leaning on her desk inside the cozy, private school she regularly attends with her sister Jyoti, 10, since 2011, and located by their newly built home in Oriya Basti, one of the water-contaminated colonies in Bhopal, central India, near the abandoned Union Carbide (now DOW Chemical) industrial complex, site of the infamous '1984 Gas Disaster'.